Vector node question
Bump Mapping and Normal Mapping

Bump mapping and normal mapping are technically the same thing. They both add fake vectors and manipulate existing ones to generate the effect of higher polygon numbers by faking geometry light reflections. Both can be used for render purposes and in game engines as well. The difference between them is the amount of information they yield. 

Bump maps are grey scale images, they provide their information using values between black and white. Normal maps are RGB images, they provide additional directional information using red, green and blue. 

The modern way to fake geometry through light reflections are normal maps due to higher accuracy. Some games still use bump maps in some cases, where the effect is less noticeable and the smaller file size reduces loading times. 

Micro Displacement (not to be confused with Vector Mapping)

Micro displacement at this point of Blender development is only possible within Cycles render engine for render purposes. At this point it cannot be baked to a texture. It works only on high-poly models and only offers benefits in conjunction with Blenders fairly new adaptive subdivision feature. 

Micro displacement provides more detail on models in general and adaptive subdivision reduces detail on objects that are further away from the camera. Combine them and you reduce render times significantly. 

Vector Mapping Node (as shown in your screenshot)

The vector mapping node is used to transform image or procedural textures. You can manipulate their size, rotation and location.